The purpose of this protocol is to characterize the local and systemic immunity in normal individuals after intradermal administration of a replication deficient adenovirus 5 (Ad5) transfer vector. A replication deficient Ad5 vector carrying the Escherichia coli (bacteria) anzyme cytosine deaminase gene (AdgvCD.10) will be administered to the skin of healthy individuals. The use of the AdgcCD.10 vector, as well as to a heterologous (i.e., non-human) gene product [the bacterial enzyme cytosine deaminase (CD)]. Because CD is not a human gene, and humans have no analogous genes, there is no safety risk to evoking immunity against CD, i.e., the study is equivalent to a vaccination study.